You might remember the story about the mountaineer who amputated his forearm so he could survive after his hand became trapped under a boulder. But imagine amputating a limb to escape a predator — again and again and again? Such is the everyday life of the otherworldly-looking lion’s mane sea slug.

Tiny marine creatures known as zooplankton feed on phytoplankton, which use photosynthesis to create their food. Since phytoplankton tend to hang out at the ocean’s surface to absorb the sun’s energy, zooplankton head there for their meals each night. But when morning arrives, zooplankton become targets for predators, so they move to deeper waters during the day.

Carrying a bit of extra fat isn’t usually considered ideal among the human population, but for corals, extra fat could be a lifesaver. The more fat reserves a coral has, the stronger its recovery appears to be after severe stress.

Of more than 300 species of octopuses, a few outliers are bound to do things a little differently. Meet the sneaky — but surprisingly social — larger Pacific striped octopus, who has some unconventional ways of taking both his meals and his mates. While most octopus species seize their prey with all eight arms before the critter can escape, the Pacific striped octopus scrunches itself together and stealthily approaches its prey from behind. It then extends just one tentacle to tap the prey, such as a shrimp, on its far side.

Fish often stick together for protection from predators. Staying within a school of fish is usually safer than swimming alone. But it turns out that some fish lend a helping fin when it comes to feeding as well.

Breeding season can be brutal — even bloody — for male elephant seals. These heavyweights take the competition for mates very seriously, with both vocal and physical threats to other males. Sometimes they rear up to show their height, and sometimes they slam their chests onto the sand to send intimidating vibrations into the ground. But despite all this posturing, actual physical fights occur less than five percent of the time in elephant seal colonies.

If a species on the brink of extinction could learn to clone itself, that nifty trick could improve its chances for survival. And that’s exactly what scientists have discovered some smalltooth sawfish are doing in Florida — reproducing without mating. This critically endangered species is one of five species of sawfish, creatures that look like a cross between a shark, a ray and a chainsaw blade. Sawfish have a long, flat snout with widely spaced teeth that protrude in a line on either side, an arrangement that is reminiscent of a saw.

Sometimes scientists go searching for one thing, only to stumble upon something completely unexpected. That’s how one group of researchers recently discovered a collection of underwater volcanoes about 150 miles off the coast of Sydney, Australia.

You might think the largest – and perhaps loudest – animal ever to roam the planet would not be hard to track. After all, blue whales can grow up to 100 feet long, weigh up to 200 tons and produce sounds that travel 1,000 miles. And yet, until recently, scientists had difficulty figuring out where these massive krill-eating creatures traveled. Now, a single female named Isabela has offered some clues.

Imagine that every time a veterinarian microchipped a dog or cat, the animal found a way to expel the microchip from its body. It turns out that is exactly what a sea star (aka starfish) does with a foreign object in its body. It pushes the object to the tip of an arm and then ejects it from its body.